In view of the depletion of fossil fuels and the prevention of a global warming, introduction of power generation systems utilizing natural energy (e.g., wind power and solar power) is advancing worldwide. A wind power generation device converts energy possessed by wind into rotation energy through a wind turbine, and transmits such energy to a power generator directly or with an increase in the rotation speed by a speed-up gear, thereby generating electrical energy. A wind farm is a system for generating large power by placing wind power generation devices of several tens to a hundred or more on a broad land or on the broad ocean.
When the scale increases, a wind farm affects a stable operation of a power system, and thus an output control performance and a system interconnection management equivalent to those of a thermal power generation plant are required. System interconnection requirements to interconnect a wind farm with a commercial system are defined by respective electric power companies and national standards.
A thermal power generation plant or a water power generation plant connected to a power system controls the frequency of power output by a generator to be within a certain range. When a wind farm having a characteristic of changing the frequency of power output by a generator in accordance with wind power is interconnected with such a power system, a load on the frequency control in the power system increases. The frequency maintaining performance decreases in the night when the thermal and water power generators in the power system are deactivated, and it sometimes becomes necessary to parallel off the wind farm.
The fluctuation originating from the wind farm also causes a voltage fluctuation at a connection point, which deteriorates the power quality. Hence, as to the output by the power generator of the wind farm, a control of ensuring a spinning reserve to be maintained, i.e., a performance that can increase supplied power to a system when a disturbance like a breakdown occurs in an interconnected power system is performed. By maintaining the spinning reserve, the wind farm can be operated as a power plant that can contribute to the system stabilization.
For a power producer possessing a wind farm, it becomes possible to increase the operating rate while avoiding unnecessary parallel off, and further to contribute to the system stabilization when a breakdown of a power system occurs by controlling the wind farm output so as to satisfy the system interconnection requirement.
Non-Patent Document 1: “System Connection Technology Requirement of Wind Power Generation Facilities (for extremely high voltage)”, December, 2011, Tohoku-Electric Power Co., Inc.
Non-Patent Document 2: Standard Number IEC61400-25-2 (Wind Turbines-Part 25-2: Communications for monitoring and control of wind power plants-Information models) Annex C, 2006 Dec. 14.
Patent Document 1: JP 2009-239990 A
Patent Document 2: JP 2007-32488 A
Patent Document 3: JP 2007-37226 A
Patent Document 4: JP 4881349 B
In order to operate the wind farm, it is desirable to set the control amount of each wind power generation device in the wind farm. In order to do so, a technology is known which calculates a control amount of the whole wind farm based on the output value of the wind farm and the output target value thereof, and which obtains the control amount of each wind power generation device in the wind farm based on the whole control amount. However, the calculation result that is the control amount of the whole wind farm usually contains various delay components.
For example, the output value of the wind farm is measured at a connection point between the wind farm and the power system, and is transmitted to a control device performing a calculation. Hence, the output value of the wind farm utilized for the calculation by the control device contains delay components at the time of transmission. Therefore, the control amount of the whole wind farm calculated based on the output value containing the delay components at the time of transmission also contains delay components.
In the calculation of the control amount of the whole wind farm, delay is inevitably caused by such a calculation. That is, the control amount of the whole wind farm which is a calculation result contains delay components inherent to the calculation.
The disclosure of the present application has been made to address the aforementioned technical disadvantages, and it is an objective to provide, for a wind farm, an output control device, a method, and a program which compensate delay components contained in a calculation result in the calculation of a control amount of the wind farm, and which distribute a control amount within an outputtable range of a wind power generation device in accordance with the present condition of wind based on a control amount of the whole wind farm having undergone the compensation of delay components.